Abstract

Introduction

In development of the American College of Rheumatology (ACR)/European League Against
Rheumatism (EULAR) rheumatoid arthritis (RA) remission definitions using clinical
trials data, one criterion used to compare different remission definitions was whether,
compared with those not in remission, those in remission had evidence of later disease
stability defined by x-ray and functional status. Validation of the RA remission criteria
using observational study data is necessary before recommending their use in practice.

Methods

Using data from those who met RA criteria in the ESPOIR cohort, we matched each person
in remission with a person not in remission and then carried out analyses comparing
later stability of x-ray and health assessment questionnaire (HAQ) between the two
groups. We compared the predictive validity of the same candidate definitions of remission
evaluated in the ACR/EULAR process. To minimize potential bias and produce more stable
results, we used a bootstrap resampling approach to select those not in remission,
repeating the sample matching analysis process 500 times.

Results

Results were similar to those of clinical trials analyzed for the ACR/EULAR remission
criteria. Specifically, the ACR/EULAR remission definitions using either an simple
disease activity index (SDAI) ≤ 3.3, clinical disease activity index (CDAI) ≤ 2.8
or a definition of remission requiring tender joint count, swollen joint count, patient
global assessment all ≤ 1 performed as well or better than other candidate definitions
of remission in terms of predicting later x-ray and function stability.

Conclusions

ACR/EULAR definitions of remission developed for trials are similarly valid in observational
studies in RA and could be used in practice.